1. Field of the Invention
The present invention relates to flat panel display systems, and more specifically, to a flat panel ferroelectric display system.
2. Description of Related Art
Ferroelectrics have the unique property of spontaneous polarization along a polarization axis. The material remains neutral internally as the end of each dipole is paired with the opposite end of the next dipole along that polar axis. At any boundary with a normal component to this axis, the dipoles are unpaired and a material dependent bound charge will exist. As a consequence of this abnormally high energy state, free screening charges collect to neutralize the surface. It is possible to eject a pulse of these charges and/or induce a field emission pulse by altering the material's internal polarization.
Experimental evidence of weak electron emission from a ferroelectric material was found as early as 1964. The popular view of the process is that ferroelectric emission results from the expulsion of the free screening charge from the material's surface upon a rapidly induced change of the internal polarization. Another possibility is that ferroelectric emission is actually a field emission process where an extremely large electric field, generated by the spontaneous bound charge, is caused to exist across a nonferroelectric layer on the surface.
The renewed interest in ferroelectric emission is attributed to the development of better emitter materials. Ceramics such as Lead-Titanate-Zirconate (PZT) or Lead-Lanthanum-Titanate-Zirconate (PLZT) can be switched very rapidly (10's of nanoseconds) compared to any characteristic diffusion or relaxation times. Further, these new materials can have an extremely high spontaneous bound charge (up to 100 .mu.C./cm.sup.2). Thus upon polarization inversion, strong emission occurs (&gt;100 A/cm.sup.2).